96 THE UNIVERSITY SCIENCE BULLETIN. 



four eggs; on the 6th, 11 eggs, on the 7th, 17 eggs. By August 31 this 

 unfertilized female had laid 47 eggs. These eggs were left under the 

 observation of a friend to determine whether any would hatch. They 

 were forgotten. In the case cited above where 8 females and 1 male were 

 placed, the male escaped July 18, but the females continued to lay fertile 

 eggs. In a third jar an egg hatched July 13. An adult female came forth 

 July 25. Placed a male with her and by August 4 there were 28 eggs, 

 which were removed. They were mating on this date. The evening of 

 August 5 there were 11 eggs. All of these were placed at the water line. 

 August 14, 78 eggs were removed. This one female in 10 days laid 78 

 eggs. The male died on the 22nd, and the rearing discontinued on 

 August 31, when 67 more eggs were removed — a total of 173 eggs in 

 about 36 days. The female was lively at the time the observations were 

 stopped. Thus it will be seen that these bugs lay many eggs and are 

 capable of laying as many as 11 in 24 hours. 



Longevity. The adults live a full season and no doubt longer. More 

 data on the longevity of the water bugs is to be desired. 



Food Habits. Kirby, 1892, made the unfortunate statement that their 

 "habits were probably herbivorous." A little patient observation would 

 have dispelled such a notion. The measured deliberation of these insects 

 in their undisturbed movements is not conducive to a quick determination 

 of their habits. One summer the writer made the practice of spending a 

 few hours each day in the observation of the normal activities of the bug 

 population of the pool. A three-foot "two by four" with a piece of board 

 nailed on one end, served as a stool that could be carried about in the 

 shallow waters and made quiet and continued observation possible. 

 It is only in such a way that one can make satisfactory notes upon these 

 insects. 



As stated by writers from the beginning, these bugs are carnivorous. 

 Kirkaldy was puzzled to note that the fore limbs were not modified for 

 the prehension of their prey, but the writer has shown that the strong 

 and retrorsely barbed stylets are quite sufficient for the retention of their 

 victim. This same morning several were seen with newly emerged and 

 still white midges. He found that the source of their food supply in the 

 main comes from organisms beneath the surface. Ostracods at the sur- 

 face film, mosquito wrigglers and pupae, and even Corixid nymphs have 

 been speared out of the water. Bueno noticed aquarium specimens put- 

 ting out their hairlike rostra and penetrating the surface film with them. 

 A closer study of this would have lead him to some interesting observa- 

 tions. In the field, the early morning is a splendid time to watch them. 

 On one pool where they were living upon a floating mass of dead cattail 

 leaves they were frequently observed. We offered them mosquitoes, but 

 although they might fall within a centimeter of them, they might investi- 

 gate indifferently but promptly turn their attention to the things that were 

 taking place at the surface film. For the activity here they were all at- 

 tention ! In one case a third instar N. undulata came to the surface 

 near an adult female. She dipped her rostrum and antennae and stealthily 

 approached. Would she hook into this creature? It surely would capsize 

 her for she was upon open water. Now a moment's survey with the beak 



